Map transparency curvature device



1 D. TANGORRA 3,103,702

MAP TRANSPARENCY CURVATURE DEVICE Sept. 17, 1963 Filed 0G12. 25, 1961INVENTOR. LOUIS D. TANGORRH am wir United States Patent O 3,103,702 MAPTRANSPARENCY CURVATURE DEVICE Louis D. Tangorra, Bronx, N .Y., assigner,by mesne assignments, to the UnitedStates of America as represented bythe Secretary of the Navy Filed Oct. 23, 1961, Ser. No. 147,108 9Claims. (Cl. 18-19) The present invention relates to curvature devicesand more particularly to devices for curving flexible members toprescribed arcs.

In map making it sometimes becomes desirable to take dat maps made bytaking conic projections of a spherical globe and produce curved modelstherefrom. The usual procedure is to draw the map on a piece of flatcle-ar plastic to conform to its drafted conic section, and by means ofa projection system, on the sensitized surface of a curved model, usethe curved map to produce a photographic image. Curving of thetransparency is done by stretching the plastic over a support conformingtothe curve of the particular conic projection. Obviously, it can beseen that if a number of models using maps of different projections areto be made, the step of producing the conic support becomes expensiveand time consuming. Thus, it becomes desirable to develop .a supportwhich can shape the plastic transparency to suit any number of differentconic sections. In addition, these supports must have certain featuresnecessitated by the nature of their function. For instance, the supportsmust not interfere with the projection of fthe transparency onto thesphere and since the transparency must conform to a conic section thedevice must be able to curve it to more than one radius of curvature.

Therefore, it is lan lobject of the present invention to produce asupport which conforms objects to a number of curvatures.

Another object tof the instant invention -is to produce a support whoseradius of curvature may be quickly and accurately changed.

Still another object of the instant invention is to produce a curvaturedevice whose radius of curvature may be easily determined.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 is a side elevation of the present invention;

FIG. 2 is la section taken Ialong 2 2 in FIG. l; and

FIG. 3 isa section taken along 3 3 in FIG. l.

Referring to the gures, a spring steel bar 10, which serves as the curvesupport of the transparency, is attached lat its center 12 by means ofIa pin dowel 14 and clamp 16 to an arcuate pivot 18` which conforms tothe minimum desired radius of curvature. 'Ille arcuate pivot 1S ispreferable Ito a knife edge support located at the center of 16 of thebar since the bending of the bar around such a support tends to form thebar to la hyperbolic function. The curved pivot decreases the tendencyof the bar to take such hyperbolic form. Likewise, the bar is taperedtowards its ends 20` and 22 to similarly minimize the tendency of thebar to take hyperbolic form.

The bending force to produce curvature yis brought at each end 20 and 22of the bar `10 by means of pivoted rods 24 and 26 which are notched 2Sat the ends to accept circular cams 30 and 32 attached to plates 34 and36 depending from the ends of the bar 10. The unnotched ends of theb-ars 24 and 26 are lformed into sector gears 38 and 40 that mesh withthe output gears 42 and 44 of a gear system driven by a shaft `46attached to a knob 3,103,702 Patented Sept. 17, 1963 ICC 2 48 :that maybe turned by an operator. Thus, rotation of the Aknob 48 will move thesector -gears 38 and 40 pivoting the rods 24 and 26 around their piv-otsso that the notched ends of the rods 24 and 26y bring pressure to bearon the circular cams 3f)` and 32 to bend the bar 10. A counter 50attache-d :to the knob 48 by a beveled gear set '52 will measure theposition of the knob for a given curvature so that the knob may -becalibrated in terms of the arc described yby the bar 10.

In operation, the arcs prescribed by the two curved extremities of aconical section are determined. The bars in two devices similar to theone described are bent to conform to these arcs by rotation of the knobs48 in each of the devices. One bar conforms to one extremity and the`other bar Ito the other extremity. These supports are then attached tothe edges of the transparency which is to be curved. Ihe transparenciesare then ready for projection.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that Within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described. 2r What isclaimed is:

0 1. A device to be used vin pairs to bend transparent maps to curvethem to their drafted sca-le curvature preparatory to their projectionon sensitized models comprising,

.a flexible bar to which the edges of a transparent map may beattached,I

4means having a curved surface attached to the center of the flexiblebar providing a pivot point on which said exible bar is bendable, andforce means coupled to said bar for bending the bar to conform to adesired curve by setting up a bending moment around the pivot point.

2. 'I'he structure of claim l, wherein the bar is tapered toward itsextremities.

3. A ldevice to be used in pairs to bend transparent maps to curve themto their drafted scale curvature preparatory to their projection on asensitized model cornprising,

a exible bar tapering from its center to which the edges of atransparent map may be attached,

arcuate curve means conforming to the map section having the smallestradius of curvature coupled to the bar at its center providing a pivotpoint on which the bar is bendable,

5() iand force means coupled to the ends of the flexible bar for bendingthe bar to the desired curve by setting up a bending moment around thepivot point.

4. A Idevice to be used in pairs to bend transparent maps to curve themto their drafted curvature prepara- :tory to their projection tonsensitized models comprising,

a tapered flexible bar to which the edges of a transparent map may beattached, means having an arcuate curved sur-face to which the flexiblebar is bendyably attached tat approximately its center thereby providinga pivot point, force means coupled :to the ends o-f the flexible bar forbending the bar to the desired curve by setting up bending momentsaround the pivot point,

and adjusting means coupled to the force means to vary the bendingmoments to obtain various radii of curvatures.

5. The structure of claim 4, including meter means coupled to saidadjusting means to determine the radius of curvature of the flexiblebar.

6. A device to be used in pairs to bend transparent maps to curve themto their drafted scale curvature preparatory to their projection onsensitized models comprising,

a tapered exible bar to which the edges of a transparent map may beattached,

means having `an arcuate curved surface to which the ilexible bar isbendably lattached yat approximately its center thereby providing apivot point, lever means slidably coupled to the ends of the ilexiblebar and pivotly secured to said arcuate surface means to bend the exiblebar around the curved surface,

and drive means coupled to said lever means tto pivot said lever meansaround said pivot.

7. The structure of claim 6, and including meter means coupled to saiddrive means to determine the radius of curvature of the ilexible bar.

8. An adjustable device to be used to bend map transparencies to variousdesired radii of curvature preparatory to their projection on sensitizedmodels comprising,

a ilexible bar to which the edges of a transparent map may be attached,

means having a curved surface attached to the center of the ilexible barproviding a pivot point on which said exible bar is bendable,

and means coupled to said bar for bending the bar to substantiallyconform in shape to the arc of a true circle.

9. The structure of claim 8, wherein the vlast named 5 comprise;

a pair of cam means, each of said cam means being coupled to an end ofthe flexible bar,

a pair of lever means, each of the llever means being coupled at one endto .the cam means,

pivot means coupled to the curved surface means and the ends of saidlever means,

and drive means coupled to said pivot means for pivoting said levermeans around said pivot point thereby bending the ilexible bar to anydesired radii of curvature.

References Cited in the le of this patent UNITED STATES PATENTS

6. A DEVICE TO BE USED IN PAIRS TO BEND TRANSPARENT MAPS TO CURVE THEMTO THEIR DRAFTED SCALE CURVATURE PREPARATORY TO THEIR PROJECTION ONSENSITIZED MODELS COMPRISING, A TAPERED FLEXIBLE BAR TO WHICH THE EDGESOF A TRANSPARENT MAP MAY BE ATTACHED, MEANS HAVING AN ARCUATE CURVEDSURFACE TO WHICH THE FLEXIBLE BAR IS BENDABLY ATTACHED AT APPROXIMATELYITS CENTER THEREBY PROVIDING A PIVOT POINT,